[lkml]   [2011]   [May]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: Identifying network namespaces (was: Network namespace manipulation with file descriptors)
On Wed, May 18, 2011 at 4:33 PM, David Lamparter <> wrote:
> On Wed, May 18, 2011 at 04:03:03PM +0300, Alexey Dobriyan wrote:
>> On Wed, May 18, 2011 at 3:43 PM, David Lamparter <> wrote:
>> > -   processes cannot easily be cross referenced with each other
>> >
>> >  in the case of user space stuff running astray - like management
>> >  software crashing, routing daemons screwing up, etc. - it becomes
>> >  fairly difficult to shut down a network namespace (or even reaquire
>> >  physical devices that have been reassigned)
>> It shutdowns itself when last process using netns disappeares,
>> so if you kill your routing daemons you should be fine.
>> Physical netdevices are moved to init_net.
> Now assume I'm running pptpd, which forks a new pppd for each
> connection. Even if I kill pptpd, the pppd keeps running... now how do I
> find the pppds that belong to that one namespace that I'm trying to
> get rid of?

That's a valid question.

>> > So, considering this set of premises (feedback welcome) I looked for
>> > some suitable means of identification. I discarded going for any process
>> > identifiers since Eric's patches allow for network namespaces without
>> > any process holding a reference, using bind mounts instead.
>> If anything it should be netns->id, /proc/*/netns outputting id
>> where id is not derived from kernel pointer.

Actually it should be symlink
/proc/net/netns -> 0 # for init_net
/proc/net/netns -> u32 (> 0) # for the rest
to extract information by 1 syscall, not 3
where netns id is totally random, so userspace won't make assumptions.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2011-05-18 16:15    [W:0.037 / U:7.876 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site